She can get 21 portions. Since 2/3 and 42/3 already share the same denominator, all you need to do is divide 42 by 2 to get 21.
The Lagrangian is

It has critical points where the first order derivatives vanish:



From the first two equations we get

Then

At these critical points, we have
(maximum)
(minimum)
The answer is step 3. Step 2 is suppose to be 3 x 7 and the answer is 21 but he writes 7 in step 4
Answer:
The standard deviation of weight for this species of cockroaches is 4.62.
Step-by-step explanation:
Given : A different species of cockroach has weights that are approximately Normally distributed with a mean of 50 grams. After measuring the weights of many of these cockroaches, a lab assistant reports that 14% of the cockroaches weigh more than 55 grams.
To find : What is the approximate standard deviation of weight for this species of cockroaches?
Solution :
We have given,
Mean 
The sample mean x=55
A lab assistant reports that 14% of the cockroaches weigh more than 55 grams.
i.e. P(X>55)=14%=0.14
The total probability needs to sum up to 1,



The z-score value of 0.86 using z-score table is z=1.08.
Applying z-score formula,

Where,
is standard deviation
Substitute the values,





The standard deviation of weight for this species of cockroaches is 4.62.
There are 24 hrs in a day, and there are 365 days in an year
first step: multiply years with days
37 x 365 = 13505 days in all
second step: multiply days with hrs
13505 x 24 = 324120 hrs
your total is 324120 hrs
hope this helps